GB453890A - Apparatus for recording sound on a film or reproducing sound from a film record - Google Patents

Abstract

453,890. Optical sound recording and reproducing apparatus. MIHALY, D. VON, 3, Hildegardstrasse, Wilmersdorf, and PINTSCH AKT.-GES., J., 71, Andreas Strasse, both in Berlin. March 21, 1935, No. 8903. Convention date, March 21, 1934. [Class 40 (ii)] Apparatus for recording sound on or reproducing sound from an endless band of film having a continuous photographic sound track extending a number of times round the band parallel to the edges of the film, the record shifting at intervals without interruption from one track to the next, comprises means for directing a narrow light beam on the film, means for driving the film in lengthwise direction, and means for causing intermittent movements of the light beam in a direction transversely of the film, the speed of said transverse movements being proportional to the speed of the lengthwise movement of the film. The Figures show apparatus for reproducing sound from an endless film 9 which is withdrawn from the inside of a coil 4 passed around a drum 8 containing a photo-cell 13 and paid on to the outside of the coil 4 as described in Specification 453,889 by a single sprocket 14 driven by a motor 16. The drum 8 is provided with a groove 10 in which is formed a narrow slit 12 opposite to which on the other side of the film is a mask 19 having an opening 20, the diameter of which is substantially equal to the width of any one of the sound tracks on the film, and through which light from a source 24 is directed by a condenser lens 25 and mirror 26. The light source, lens, mirror and mask are all carried by a frame 22 slidably mounted within the drum 8. The means for causing transverse movements of the light beam consists of a threaded spindle 30 passing through a nut 31, the upper end of the spindle bearing against a projection 29 on the frame 22 whilst its lower end carries a friction disc 32 against which a second loose rotatable friction disc 33 driven by a cord 36 from the motor 16 is pressed from below by a spring 34. The disc 32 is normally prevented from rotating by the armature 38 of an electromagnet 37 which engages against a pin 39 thereon. When, however, a roller 41 engages with a notch 42 in the edge of the film, a switch 40 is closed to energize the electromagnet 37, the armature 38 is raised and the disc 32 allowed to make a single revolution so as to raise the light beam to register with the next sound track. If desired, a handle may be provided to lift the armature 38 to allow the light beam to be registered with any desired sound track. Specification 453,888 also is referred to. The Specification as open to inspection under Sect. 91 comprises also a modification in which a two-armed lever is provided between the projection 29 and the spindle actuated by the disc 32. This subject-matter does not appear in the Specification as accepted.